Conflicts today are longer — more than 20 years on average — and often involve multiple armed groups competing for control of government institutions, natural resources and territory, the U.N. chief said Wednesday.

Secretary-General Antonio Guterres told a Security Council meeting on the growing complexity of challenges to international peace and security that “we are seeing not only a quantitative but also a qualitative change.”

“The perils of nuclear weapons are again front and centre, with tensions higher than they have been since the end of the Cold War,” he said.

Guterres didn’t name any countries but he has repeatedly urged North Korea to halt its escalating nuclear and ballistic missile tests.

The secretary-general also said “cybersecurity dangers are escalating,” climate change has emerged as “a threat multiplier” and water scarcity is “a growing concern.”

He further warned that inequality and exclusion are feeding “frustration and marginalization.”

While there has been a long-term decline in the number of armed conflicts, Guterres said “conflicts have surged” in the Middle East and parts of Africa.

Conflicts are also “becoming more intractable,” he said, and they are becoming more regional and international.

Guterres said political factions and armed groups are also multiplying, with hundreds of armed factions in Syria alone.

“External military and financial support to conflict parties prolongs civil wars — and fuels wider tensions as local fights become proxies for larger rivalries,” Guterres said.

“Conflicts are more linked with each other, and with the worldwide threat of terrorism,” he said. “And transnational drug smugglers and human traffickers perpetuate the chaos and prey on refugees and migrants.”

Guterres said the U.N. must rethink its approaches to respond to the changing nature of conflicts — and prevention must be the key.

He said achieving U.N. goals, such as ending extreme poverty, promoting economic development, protecting the environment, addressing climate change and achieving equality for women, are among the best “instruments of prevention.”